CZ457 MTR Match Chamber

[Nick Caprinolo]

Last July I bought a CZ457 MTR. It came with a match chamber. I have tried at least 11 different ammos in it and have had some difficulty chambering all but one bullet type. Eley Tenex will chamber with no trouble. Slides in as smoothly as glass. Anything else must be forced in. Some more than others. I have shot about 700 rounds through it, so I think that's enough to say the action should be broken in.

Anyone else experiencing this?

 

[gkgeiger]

Mine doesn’t like Eley products. Loves all Lapua including all SK. SK Std. + shoots great. Norma works good also but I’m a Lapua fan.

 

[ROBARRC50]

Mine has run cci , eley , rws and sk perfectly so far.

 

[DGP4]

Match chamber wants match ammo. There is a lot of variation in .22LR ammo by manufacturer. It is not unusual to have the ammo fit tight in a match chamber as the bullet is pressed into the grooves. It could be that CZ uses a reamer specifically matched to Eley ammo. A call to CZ USA should clear that up.

 

[HuskerP7M8]

Last July I bought a CZ457 MTR. It came with a match chamber. I have tried at least 11 different ammos in it and have had some difficulty chambering all but one bullet type. Eley Tenex will chamber with no trouble. Slides in as smoothly as glass. Anything else must be forced in. Some more than others. I have shot about 700 rounds through it, so I think that's enough to say the action should be broken in.

Anyone else experiencing this?

Considering CZ seems to often have problems with HS, it's quite possible the HS of your rifle may be 0.043" or less.
Lapua and some others manufacturers almost always have thicker rims vs Eley, and that may be the problem.
While possible in certain circumstances, engraving of the bullet up to 0.100"+ in the driving bands, doesn't normally cause a major problem.

Landy

 

[bsekf]

Have you tried cleaning the chamber? 22rf is so dirty, even the good stuff.

 

[SGW Gunsmith]

I currently own CZ .22 rimfire rifles, a CZ 455 FS and a CZ 455 LUX with a CZ 457 MTR on the way. On the two that I now have, I haven't found a chambered round engaging the leade 0.100 of an inch. That's almost 1/8, but rather more like 0.010 thousandths of an inch, like so:

Here's a very simple and cheap way to get accurate rim thickness measurement. Using a fired .22 centerfire case, measure the overall length:

Then, zero out your caliper:

Insert a .22 rimfire round:

Then again, measure the overall length:

 

[SBS]

Have you tried cleaning the chamber? 22rf is so dirty, even the good stuff.

It's possible this may be the problem, and/or there could be a build up of lead in the throat. Since match chambers are made to engrave the rifling, it usually builds up in a newly chambered barrel unless cleaned frequently. Chambering always leaves a small burr laid over on the down side of the reamer and unless lapped out, you have to clean frequently (may have to use a bronze brush) until the rounds have lapped it out. Once it leads up, no removal of the burr happens and rounds get more and more difficult to chamber. Build up of bullet lube in the chamber can also cause chambering problems. I purchased a new Anschutz 54 some years ago and followed the factory instructions on cleaning -- using light solvent and oil. Rounds became harder and harder to chamber. Taking a look in the throat showed a considerable build up of lead. A bronze brush solved the immediate problem and used it for quite awhile until the throat was smoothed out.

 

[Nick Caprinolo]

Let's set the record straight.

I clean this rifle's throat, using a AR15 breach brush. I do this after 50 rounds. I further clean the bolt face at the same time. As for the bore, I pass a clean patch through it before and after each shooting session. The breach and bore are perfect, showing absolutely no tool marks. I just finished shooting the 500th round through it and will now give it a thorough cleaning using solvent and oil. I scoped the rifle last night and it still has a mirror finish even though I only passed a dry patch through it.

 

[SBS]

That's good info. If not a cleaning or leading problem, the cartridge fit may be. Remember that a true match chamber will require the leverage of the bolt to finish chambering the round fully, pushing the bullet into the rifling. Good way to check and see if the cases of the troublesome brands are the problem is to pull the bullets from them and see how they fit in the chamber without bullets. If they are still a tight fit, you could have insufficient headspace or the chamber could be a little small in diameter, particularly near the rim. Not too many possibilities for this problem.

 

[1911nut]

Nick, how does the rifle group with its favorite brand of ammo?

 

[Nick Caprinolo]

Nick, how does the rifle group with its favorite brand of ammo?

Most times it shoots 3/4 or less 5 shot groups at 50 yards. Not bad, but no cigar.

My Mod54 Anschutz which is 67 years old and all original, will constantly shoot 3/8 or less.

 

[CharlieNC]

My MTR is on the way back from CZ who replaced the barrel after it suddenly became impossible to chamber a round, after firing around 750. A bore scope revealed the paper thin wall between the extractor grooves and the chamber was damaged. If you have a scope inspect the chamber carefully, it sounds like this not an uncommon issue.

 

[Mythbuster]

There is absolutely nothing wrong with your gun. Its engraves the rifling when you chamber a round and the headspace it tight

 

[Mythbuster]

Basically the MTR has the tightest possible chamber that industry specs will allow. You are not going to be able to close the bolt on a live round as easy as you would on the average .22 rifle.

 

[grauhanen]

Basically the MTR has the tightest possible chamber that industry specs will allow

All CZ .22LR rifles chambers are made according to CIP specifications, as are those of all firearms made in CIP countries. CIP establishes the minimum chamber dimensions allowed and these dimensions are known because they are published (see below). The actual chamber dimensions of the CZ match chamber may exceed the minimum allowed. With CIP rifles it's likely that the chamber length varies more than the chamber diameter. Longer chambers will allow the easier use of a wider variety of ammos.

Only CZ itself and those able to accurately measure the CZ match chamber size know the actual dimensions of the "CZ match chamber". Whatever they are they will not be less than the CIP minimum dimensions.

 

[mike185]

Last July I bought a CZ457 MTR. It came with a match chamber. I have tried at least 11 different ammos in it and have had some difficulty chambering all but one bullet type. Eley Tenex will chamber with no trouble. Slides in as smoothly as glass. Anything else must be forced in. Some more than others. I have shot about 700 rounds through it, so I think that's enough to say the action should be broken in.

Anyone else experiencing this?

got a new onevwith mtr it wont take several brands of ammo.on sk match it wont fire and it leaves the loaded rd in another the rd only goes in half way. bummer

 

[Appalachian]

I have two MTR’s. I can shoot CCI SV, Federal Automatch and all types of SK, Lapua and Eley. The bolt takes a little more force to close on CCI and Federal, but nothing crazy. Both of mine prefer SK and Lapua over Eley.

 

[wildphil]

With my MTR with Eley ammo the bolt is harder to close. Eley. Contact was the worst of all that I have tried so far. With Tenex the bolt is just slightly harder to close. Lapua and SK chamber and the bolt closes normally. Cheaper ammo does not work so well. I tried some Winchester Wildcat. That stuff was to tight for the chamber and would not extract well at all.

 

[Racerman56]

With my MTR with Eley ammo the bolt is harder to close. Eley. Contact was the worst of all that I have tried so far. With Tenex the bolt is just slightly harder to close. Lapua and SK chamber and the bolt closes normally. Cheaper ammo does not work so well. I tried some Winchester Wildcat. That stuff was to tight for the chamber and would not extract well at all.

I would say I had the same results as wildphil.